( 2014-11-09)


  1. “Login Definition.” The Linux Information Project 2004. Web. Link (remote) →
  2. “Home Directory Definition.” The Linux Information Project 2004. Web. Link (remote) →
  3. “Root Directory Definition.” The Linux Information Project 2004. Web. Link (remote) →

User login

  • A “login” is the act or procesure of “logging in” or “loggin on” to a computer system
  • One “logs in” as a user
  • A user is identified and authenticated by the system using:
    1. A text user name
    2. A text password
      • There is significant pressure on the convention of text password security, today, and biometric alternatives are entering the everday consumer market (e.g., Apple’s TouchID); but in 2014 text password security remains the most common form of authentication in consumer computing
  • This information is entered by the user into a login console or window
  • The system records this information in an access log

User account

An account is a specific example of the general concept of a domain, in computing

  • Today, one “logs in” to an account assigned to oneself as a user

  • Accounts in banking
    • Not a physical space set aside exclusively for your use
      • Contrast with safe deposit box
    • An abstraction or virtual space containing your assets
  • An account is defined by:
    1. A configuration of access privileges, for access to computing resources
    2. A demarcation and assignment of virtual space in memory, for the storage and manipulation of data objects: the home directory

Home directory

  • Tree structure
    • Filesystem root
      • “Top” (or bottom) of filesystem tree
      • In Unix, one root for the entire filesystem
      • In Windows, one root for each storage device and/or partition of a storage device
    • Filesystem tree

Abstract concept of network

  • A concept of space defined not by boundaries as much as by relations
  • Generic elements of a network are often called nodes, especially in telecommunications and computing
  • Often does not have an obvious single center, though it will almost always include clusters

  • “Networking”: an adaptation to describe a social process (example)

Networked computing

  • A network includes any two or more individual computer systems connected by a telecommunications link
  • The telecommunications link may be a “tube” (hardware wire or cable), or a radio wave (transmitted and received by other hardware components)
  • When the two or more systems occupy the same relatively local space (for example, a company office or a college campus), we call the network a Local Area Network (LAN)
  • When the two or more systems are located on separate Local Area Networks, they may be linked by the Internet, a “ubiquitous” network-of-networks

Prehistory of today’s ubiquitous networked computing

  • Earliest commercial telecommunications infrastructure: telegraph and telephone wires
  • Earliest form of remote (non-LAN) desktop PC networking: via telephone lines, using an acoustic coupler modem

Representations of networked computing

Layered domains

  • Your user account is a “small” domain, which you log into
  • Your user account grants you access to computing resources like processing time and storage space for your files
  • It also serves as a portal to a larger domain: a LAN
  • And also as a portal to an even larger domain: the Internet

Game as constraint

  • Also a representation of space, a virtual space
  • Whereas a network is often imagined as boundless, a game is embraced as a system of constraint: that’s often precisely why we enjoy it
  • A game represents constrained choices for a human player’s avatar
    • For many of us, often more constrained than many of even our most quotidian life choices: for example, what to eat for lunch
  • Example: tic-tac-toe
    • Nine possibilities for placing your mark, from the start
    • Limited number of combinations of marks
    • Limited number of possible outcomes
  • All games are systems of constraint
  • Computer games (video games) are programmed
  • The human player is less free to break the rules than she or he is in games played outside simulated environments

Early computer games

Graphical (video) games

  • Spacewar! (1962)

Text (“adventure”) games

  • Terminal-based
  • Sometimes incorporated “graphics” composed with ASCII characters, rather than painted with screen pixels
  • Narrative form: an environment is described, choices are offered
  • Very explicitly algorithmic: if choice A, consequence B
  • Early examples
    • Colossal Cave Adventure, 1976
    • Zork (1977)


  • Paradigmatic form of a programmed game: the maze
  • Maze as map of programmed space

  • Programming as determination of outcomes
  • Algorithmic expression of “choice”

Mass-produced consumer games: history

  • “Primitive” games, extreme constraint
  • Often only one or two courses of action
    1. Move an avatar through a representation of space
    2. Make or cause impact with objects

Mimicry of sports pastimes

  • Pong (1972)
  • Breakout (1976)

Fictional worlds and scenarios

  • Space Invaders (1978)
  • Asteroids (1979)

Evolution of visual representation of space of constraint

  1. “Flat” (two-dimensional), with player avatar at center
  2. Three-dimensional, depicted from point of view of player avatar
    • Mid-1980s: exploration of “3D” or first-person navigational perspectives
      • Maze War (1985)
    • Early 1990s: developed into later generation of games, “first person,” usually shooter
      • Depicted space primarily or exclusively from player’s subjective POV
      • Map overlay as secondary feature
      • General increase in graphical detail and speed (hardware advances)
      • Construction of objects: polygons (3D)
      • Outdoor landscapes
      • Vertical navigation: moving up and down in space
      • Expansion of navigable space for avatar (“rails” vs. roaming)